Quantum-limited estimation of the difference between photonic momenta via spatially resolved two-photon interference

TL;DR

This paper introduces a quantum sensing protocol that uses spatially resolved two-photon interference to precisely estimate the three-dimensional difference in photon momenta, achieving quantum-limited accuracy with minimal measurements.

Contribution

The authors develop a novel 3D quantum sensing protocol utilizing spatially resolved two-photon interference, demonstrating its efficiency and precision for multi-parameter quantum estimation.

Findings

Achieves quantum-limited precision with ~2000 measurements

Bias below 1% in parameter estimation

Potential applications in high-precision 3D localization

Abstract

We present a quantum sensing protocol for three-dimensional estimation of the difference between the momenta of two photons based on spatially resolved interferometric sampling measurements. The protocol attains ultimate quantum precision in the simultaneous estimation of the components of the relative momentum for any values of the parameters already with $\sim 2000$ sampling measurements and a bias below $1\%$. These results identify 3D spatially resolved two-photon interference as an efficient tool for multi-parameter quantum sensing, with potential applications in high-precision 3D localization, refractometry, and near-field calibration in free-space quantum technologies.